If basal rate is 0.05 E/h and you increase with 95% what happens?

Type 1 & LADA
1

Hi all!

We cant increase basal rate temporarily more than 95% with our PDM for omnipod DASH. I would assume that when basal-rate is increased from 0.05 E/h to ~0.09 E/h that it rounds it up to 0.1 E/h and delivers that instead of 0.05 ? Else it would make no sense to temporary increase basal rate if the rate is 0.05 since omnipod DASH cant deliver less than 0.05 at a given time.

Anyone knows for sure? Hard to tell from logs from Glooko.

2

I am going to go out on a limb here, I use basal all the time to help control my bg, on average for last 4weeks my basal/bolus is 80% basal. And my basal is pretty much dialed in.
Now for your question, you realize omnipod delivered micro bolusus every 5 minutes to match your unit per hour setting. I am not sure your value listed for basal is per hour or what, that would be a very small amount. But when you do a temp basal it will add that amount to your normal setting and deliver that in 5 minute increments. There is no rounding off. For the duration of time you select.
Hope this helps.

3

Thanks for replying :slight_smile:

As far as I’ve learned omnipod dash delivers basal in small doses (0,05U at every pulse, it can’t deliver less than 0,05U). So if the rate is 0,05 U/h and I increase it by max (95%) to ~0,09 U/h what happens in terms of insulin delivered?

Does it deliver 0,05 in two pulses in total of 0,1 U or does it round it down (like it does with bolus-doses) to 0,05 and only delivers 0,05U that hour since it cant deliver 0,04.

When basal-rate is 0,05 U/h the entire night for my son, this is a great deal to understand how works in terms on how to managing fever etc.

4

Wow, I never knew you could set a rate that low, would be interested in knowing how pump deals with that low rate, I mean if you are directing pump to give hourly dose equal to minimum micro dose.

5

@Olorin, on the old version of the PDM, you can pick whether you want temp basals to be in terms of units or percentage.

If you can do that on your version, change temp basal to be in units. Then you can pick whatever you want.

2 Likes
6

In my omnipod DASH PDM i got no such option unfortunately.

However I found my answer.:slight_smile:

Basal insulin are given in pulses of 0.05. So this happens when an hourly dose is increased to 0.09:

1st hour: 1 puls given 59th minute of 0.05. Excess insulin of 0.04 is transfered to next hour since pod can’t deliver less than 0.05

2nd hour: total of basal insulin to be given: 0.09+0.04=1.13
Given in two pulses of 0.05 the 29th minute and 59th minute.

and so on. Pod always rounds DOWN, so keep that in mind when increasing basal for 1 hour. for this case increasing for 2-5 hours is the solution to give more.

7

0.09+0.04=0.13 but the pulses work out correctly anyway of 0.05 each. Then the 0.03 carries on to the next hour I’m assuming And that method follows forward in the same manner for all future hours.

8

You can change the Dash PDM to use units instead of a percentage. Go to settings - then choose Basal & Temp Basal. You just have to slide the Temp Basal- configuredto use flat rate (U/hr)

Its always the first thing I change on a Omnipod PDM. The percentage increases and decreases just have never made sense to me.

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2 Likes
9

thank u will have a look, cant say I have seen this option but maybe my eyes have played tricks on me :slight_smile: I live in Norway so there could be differences but I agree it makes more sense to adjust to flate rates instead of percentages. :slight_smile:

1 Like
10

I just tested (something similar to) this!

  • set TBR to 0.60
  • waited to hear a click
  • waited to hear another click (to validate my approach)
    • this happened 5 minutes after the first click, as expected (0.60U/h = 0.05U/5 min = 1 click every 5 minutes)
    • I’ll call this T+0
  • T+2:20, cancelled the TBR and set a new TBR of 0.30U/h (1 click every 10 minutes)
    • it took a non-zero amount of time to cancel the first TBR and then more time to set the new one, so the new TBR was in effect at about T+2:40
  • the next click came at ~T+7:40
  • this is pretty much what it would look like if it accumulates “progress towards a click”, and carries that forward across changes in basal rate
  • this is also the basically sane thing for it to do; it’s approximating what you told it as closely as possible, given it can only deliver insulin in clicks
  • based on this, I strongly suspect that percentage basal changes just speed up / slow down the “passage of time” in the pod, i.e something like (in code):
  if (temp_basal_rate_set)
    effective_basal_rate = temp_basal_rate
  else if (temp_basal_percent_set)
    effective_basal_rate = basal_rate * temp_basal_percent
  else
    effective_basal_rate = basal_rate

  accumulator += effective_basal_rate / 3600.0
  if (accumulator >= 0.05) {
    deliver_insulin_click()
    accumulator -= 0.05
  }

and it would run that every second. (Something to roughly that effect anyway.)

@Olorin, did you test it? I’d be surprised if the pulses fell in the 29th and 59th minute like you said.